Packing



Oct. 25, 1966 D. H. MOELLER ETAL 3,281,307

momma Filed Nov. 5, 1962 2 Sheets-Sheet l De/m er 6. Mo e//er Frank 5. flaws/e9 Char/e51: Moss W 5 INVENTORS.

Oct. 25, 1966 D, MOELLER T 3,281,307

PACKING Filed Nov. 5, 1962 2 Sheets-Sheet 2 INVENTORS. Oe/rner H. Moe //er Frank 5. TOM/S/ey Char/a5 F M0 55 United States Patent 3,281,307 PACKING Delmer H. Mueller and Frank E. Towsley, Midland, Mich, and Charles F. Moss, Cleveland, Ohio, assignors to The Dow Chemical Company, Midland, MlclL, a corporation of Delaware Filed Nov. 5, 1962, Ser. No. 235,189 8 Claims. (Cl. 161-68) This invention relates to packing. It more particularly relates to improved extended surface elements for use in gas-liquid contact systems, biological oxidation towers, and the like.

Generally, much difficulty has been encountered in the use of thermoplastic resinous materials in extended surface installations for biological oxidation, gas-liquid contact structures such as cooling towers, and the like. Frequently when using thermoplastic resinous materials the height of the packing is severely limited by the relatively low physical strength of the packing material. Often this difliculty is overcome by providing support for the bundles or packings at relatively close intervals within the tower. Thermoplastic resinous packing materials will usually give adequate service when packed to a given depth in a tower but unexpected changes in the material being treated will give rise to the growth of heavier layers of bacteria than were originally intended for the installation. Oftentimes this results in the collapse of the internal packing structure.

It is an object of this invention to provide an improved extended surface element for gas-liquid contact structures.

It is a further object of this invention to provide a configuration of extended surface element which minimizes the possibility of free-fall of a liquid from the top to the bottom of the tower.

It is another object of this invention to provide an extended surface element having significantly improved compressive strength over those known to the prior art.

It is a further object of this invention to provide an extended surface element which is readily manufactured and assembled.

It is still another object of this invention to provide an extended surface element having the foregoing beneficial properties and the ability to nest, thus requiring a minimum of shipping space.

These benefits and other advantages in accordance with the invention are readily achieved by providing an extended surface element comprising a sheet, said sheet being generally rectangular in form and having a plurality of corrugations formed on a portion of the sheet and a plurality of generally parallel corrugations formed on the remaining portion of the sheet, the corrugations on opposite portions of the sheet having their peaks displaced by about 180 and the corrugations on opposite portions of the sheet having a sinusoidal transition section therebetween.

Further features and advantages of the invention will become more apparent when the following specification is taken in connection with the drawings wherein:

FIGURE 1 is an isometric representation of a sheet in accordance with the invention;

FIGURE 2 represents a cross section of the sheet of FIGURE 1 taken along the line 22;

FIGURE 3 is a cross section of the sheet of FIGURE 1 taken along the line 3-3;

FIGURE 4 is a cross section of the sheet of FIGURE 1 taken along the line 44;

FIGURE 5 is an isometric view of an assembly of several sheets in accordance with the invention into a tower packing bundle;

FIGURE 6 is an enlarged plane view of a portion of the bundle of FIGURE 5.

3,281,307 Patented Oct. 25, 1966 In FIGURE 1 there is illustrated an isometric view of a sheet in accordance with the invention generally designated by the reference numeral 10. The sheet 10 comprises two portions 10a and 10b. The portion 10a defines a plurality of corrugations 11 having peaks 12 and troughs 13. The corrugations 11 of the portion 10a extend toward the sheet portion 10b. The peaks 12 are formed to define cup-like projections and corresponding depressions 15 on the opposite side of the sheet. The troughs 13 are provided with the projections 15. The sheet portion 10b similarly defines a plurality of corrugations indicated by the reference numeral 17. Each of the corrugations have a peak 18 and a trough 19. In each peak 18 and trough 19 of the corrugations 17 there are defined cup-like depressions 21 and 21 respectively. The corrugations 17 run generally parallel to the corrugations 11 and are displaced about therefrom. Disposed between the corrugations 11 and the corrugations 17 is a smooth transition section 22.

In FIGURE 2 there is illustrated a cross section of the portion 10b taken along the line 2-2 of FIGURE 1 showing the peaks 12 and the troughs 13 and the configuration of the cup-like depressions 15 .and 15' within the peaks and troughs 12 and 13.

FIGURE 3 illustrates a section of the sheet 10 along the line 3-3 of FIGURE 1 which depicts the configuration of the smooth transitional portion 22 between the portions 10a and 10b.

FIGURE 4 is a cross section of the sheet portion 10b taken along the line 44 illustrating the relationship between the corrugations 17 having peaks 18 and troughs 19 and the location of the generally cup-like depressions 21 and 21.

FIGURE 5 depicts an isometric view of an extended surface tower packing element or bundle generally designated by the reference numeral 30. The bundle or element 30 comprises a plurality of individual sheets 32 having a configuration substantially similar to the sheet 10 of FIGURE 1. The sheets 32 comprise two general portions 32a and 32b and are arranged in such a manner that the portion 32b is secured to the portion 32a of the adjacent sheets, thus forming a plurality of passageways 34. The configuration of the resultant structure or bundle 30 is more clearly shown in the enlarged fractional plan view of FIGURE 6 wherein there is illustrated a portion of the bundle designated as 30a. The portion of the bundle 30a comprises a plurality of sheets 32. The upper portions of the sheets 32 designated as 32a and 32b define passageways 34. The passageway 34 extends through the entire bundle and divides into similar passageways on the opposite side. The portion 32a has a peak 36 and a trough 37, whereas the portion 32b defines a peak 38 and troughs 39. The adjacent sheet portions are secured in peak-toatrough relationship. Similarly the oppositely disposed portions of the sheet define a similar pattern of passageways 0n the opposite face of the bundle not shown.

Sheets and bundles in accordance with the present invention are readily prepared from a wide variety of methods such as compression molding, vacuum forming, and the like. Beneficially the sheets utilized in preparing a packing bundle have generally identical configurations to each other which permits them to be readily stacked in nesting relationship for storage. In order to assemble a bundle or extended surface tower packing element from sheets in accordance with the invention, it is only necessary to stack sheets from the nested configuration by rotating alternate sheets 180 in the plane of the sheet, for example, if a plurality of sheets 10 such as are shown in FIGURE 1 are to be formed in a packing bundle and they are stacked in nesting relationship, the first sheet in the bundle may be rotated 180 about the axis generally perpendicular to the plane of the sheet. The rotated sheet is then affixed to the adjacent nonrotated sheet, the assembly of the two sheets rotated 180 about the same axis and secured to the sheet on the stack. Thus, the sheets are readily assembled into an extended surface tower packing element of a desired size.

The sheets are joined together by a variety of means including heat sealing, adhesives, mechanical fastenings such as screws, bolts and the like.

A particularly beneficial and advantageous method for the assembly of sheets into tower packing bundles is that of flange welding. Sheets are assembled into a generally rectangular bundle and the edges of the bundle lying in a plane generally perpendicular to the direction of the corrugations is pressed against a hot platen or similar surface causing the edge portion to deform and bond to the adjacent sheet in a manner similar to that described in United States Patent 3,007,834. This technique of assembly provides a rapid method of preparing a packing bundle that is particularly adapted to field assembly. Thus, a plurality of corrugated sheets in accordance with the invention may be shipped in closely nested relationship. On arrival at the destination a suitable number of sheets are then removed from the shipping package and alternate sheets rotated 180 about the axis of the sheet extending generally normally therefrom. By this motion a bundle generally as shown in FIGURE is formed.

A particularly advantageous configuration for sheet members utilized in the practice of the present invention is shown in FIGURE 1. The transition section between the sheet portions is so constructed and arranged that any cross section of the transition section has a generally wavy configuration. By way of further illustration, such a transition section can be generated by cutting a corrugated sheet at an angle of about 45, inverting onehalf of the sheet, that is, rotating it 180 about an axis lying in a centrally disposed corrugation, placing the two sheet portions generally adjacent to each other with the corrugations in colinear arrangement, displacing the corrugations of the adjacent sheet portions 180, that is, placing the peaks of one sheet generally adjacent to and spaced from the troughs of the second portion, joining the generally adjacent troughs and peaks by means of a plurality of straight or smooth curved lines each of which will lie in a plane which is perpendicular to the general plane of the corrugated sheet and parallel to the direction of the corrugations. This construction results in a transition section which does not have a linear or rectangular cross section but is wavy or corrugated. The angle of 45 and the particular spacing utilized can be varied to suit the particular product being prepared. This is one of the methods which is utilized to generate such a transition section. It results in a much more rigid structure than if a linear or rectangular cross section configuration exists in the transition section. The dotted lines of FIG- URE 1 indicate the adjacent ends of sheet portions which have been cut at an angle of about 45 and the transition section generated using the generally hereinbefore described method. By way of further comparison, the initial steps of separating a sheet were done by cutting at an angle of about 90 to the plane of a sheet, the resultant transition section generated by this method would have a linear or rectangular cross section at a point midway between the two sheet portions. However, as is obvious, by suitable variation this linear portion is readily avoided.

Particularly beneficial and advantageous is the configuration depicted in FIGURES 1, 2, 3 and 4 wherein small depressions are provided in the peaks and troughs of the sheet which permit the interfitting of the depression in the peaks and troughs with the corresponding protuberance developed when the depression is formed. Thus there is considerable tendency for the sheets to lock into the desired position whether it be in the nested or expanded form. Beneficially an adhesive material may be placed on the protuberance and along the peak carrying the protuberance and the sheets assembled into the expanded configuration which results in a strong uniform bond between the peaks of one sheet and the troughs of the adjacent sheet.

An alternate method which may be used for joining the sheets in accordance with the invention is to heat seal them at the junctures of the protuberances of adjacent sheets. This is readily accomplished by conventional heat sealing means employing heated platens generally similar in form to the electrodes of a spot welding apparatus. Dielectric heat sealing, i.e., the use of high frequency electric field also provides a method. Such heat sealing may also be accomplished by passing a heated rod through the sheets to be joined at the points of contact of the protuberances and the depressions. This result-s in forming a seal generally similar to an eyelet. The technique is well known in the art.

Sheets in accordance with the invention may be readily fabricated from a wide variety of thermoplastic resinous materials. Generally, however, for most purposes those thermoplastic materials which are relatively rigid under normal conditions are usually preferred such as the alkenyl aromatic resin typified by polystyrene, unplasticized rigid polyvinyl chloride, poly amides, sarans including such copolymers as are prepared from 15 parts of vinyl chloride and parts of vinylidene chloride, 10 parts of acrylonitrile and parts of vinylidene chloride, polyolefins such as polyethylene, polypropylene, and resinous copolymers thereof, polyethylene terephthalate, cellulose acetate, ethyl cellulose, polyacrylates including polyethyl acrylate, polymethyl methacrylate, polyolefins such as chlorinated polyethylene, chlorinated polypropylene and the like. Because of the regular geometry of the sheets of the invention they are readily formed from plastic materials by means of small rolls of suitable contour. By the term small rolls is meant that the circumference of a roll is substantially less than the long dimension of the article being formed. This characteristic permits rapid fabrication with relatively low equipment cost. Beneficially, there also may be employed in the practice of the invention sheets fabricated from such thermosetting resinous materials as phenyl formaldehyde resins, furfural resins, furfuryl alcohol resins, melamine formaldehyde, phenol furfural, and the like.

The configuration of packing bundles prepared in accordance with the invention is such that when two layers of bundles are placed one on top of the other and the individual sheets of the bundle are disposed in a vertical plane free-fall of the liquid throughout the stacked bundles is not possible. Thus, a space packed with bundles of the present invention permits the application of the liquid to the upper edges of the bundles by any convenient means such as spraying, fine streams, and the like, and eliminates the possibility of any of the liquid which is being treated reaching the bottom of the space without contacting a treating surface. The geometry of the sheets of the present invention is such that relatively high compressive strength is obtained. The high compressive strength of bundles in accordance with the invention permits the use of significantly greater distances between support members within the space being packed and conversely the erection of higher packed beds than comparable sheetlike structures of the prior art.

By way of comparison, tower packing bundles of sheets in accordance with the present invention were prepared and fabricated into a bundle about 38 inches long, 30 inches wide and 12 inches high. Two such bundles were placed one on top of the other and crushed in a compression testing apparatus. The bundles failed under a pressure of 1400 pounds per sheet. The precise dimensions of the corrugations and the sheet employed in the practice of the invention will depend upon the particular application for which the sheets and bundles are intended.

As is apparent from the foregoing specification, the method and manufacture of the present invention are susceptible of being embodied with various alterations and modifications which may differ particularly from those that have been described in the preceding specification and description. For this reason, it is to be fully understood that all of the foregoing is intended to be merely illustrative and is not to be construed or interpreted as being restrictive or otherwise limiting of the present invention, excepting as it is set forth and defined in the hereto appended claims.

What is claimed is:

1. A bundle of extended surface elements comprising a plurality of plastic sheets,

each sheet being generally rectangular in form and having a plurality of generally sinusoidal parallel corrugations formed on a first portion of the sheet and a plurality of generally sinusoidal parallel corrugations formed on the second portion of the sheet, the corrugations of the first and second portions extending inwardly toward the second and first portions respectively,

the corrugations on the first and second portions of the sheet having their peaks displaced by about 180, the corrugations of the first and second portions having dimensions in a direction parallel to the corrugations in a ratio of about 1:1 and the sheet portions having a smooth curved transition section therebetween, the transition section has a cross-sectional configuration in any plane normal to the direction of the corrugations which is non-linear, the sheet being so constructed and arranged that a like sheet placed in face to face engagement therewith will nest and on rotation of one sheet about 180 in a plane containing the corrugations that adjacent sheets will define a plurality of passageways therebetween generally parallel to the corrugations, the sheets being positioned with adjacent peaks and troughs of the corrugations of adjacent sheets in generally contiguous relationship, adjacent sheets being affixed to each other.

2. The bundle of claim 1, wherein each portion of the sheet and the transition section have dimensions in a direction parallel to the corrugations of the sheet having a ratio of about 1:121.

3. The bundle of claim 1, wherein the corrugations run in a direction substantially normal to the major dimension of the sheet.

4. The bundle of claim 1, wherein at least one protuberance is formed on at least one of the corrugations of said sheet.

5. The bundle of claim 6, wherein the protuberances are formed on the peaks and the troughs of the corrugations and each of the protuberances on the peaks of the corrugations interfit with the rear of a protuberance on a trough of a similar sheet.

6. The bundle of claim 1, wherein said sheets are affixed to each other by their adjacent edge portions.

7. The bundle of claim 1 having a substantially rectangular form.

8. The bundle of claim 1, wherein said sheets are a thermoplastic resinous composition.

References Cited by the Examiner UNITED STATES PATENTS 752,775 2/ 1904 Hinkel 229- 1,908,389 5/ 1933 White 217-21 1,967,026 7/1934 Gray et a1. 2l7-2l FOREIGN PATENTS 157,332 4/1922 Great Britain.

20,269 7/1909 Norway.

ALEXANDER WYMAN, Primary Examiner.

R. A. FLORES, Assistant Examiner. 

1. A BUNDLE OF EXTENDED SURFACE ELEMENTS COMPRISING A PLURALITY OF PLASTIC SHEETS, EACH SHEET BEING GENERALLY RECTANGULAR IN FORM AND HAVING A PLURALITY OF GENERALLY SINUSOIDAL PARALLEL CORRUGATIONS FORMED ON A FIRST PORTION OF THE SHEET AND A PLURALITY OF GENERALLY SINUSOIDAL PARALLEL CORRUGATIONS FORMED ON THE SECOND PORTION OF THE SHEET, THE CORRUGATIONS OF THE FIRST AND SECOND PORTIONS EXTENDING INWARDLY TOWARD THE SECOND AND FIRST PORTIONS RESPECTIVELY, THE CORRUGATIONS ON THE FIRST AND SECOND PORTIONS OF THE SHEET HAVING THEIR PEAKS DISPLACED BY ABOUT 180*, THE CORRUGATIONS OF THE FIRST AND SECOND PORTIONS HAV ING DIMENSIONS IN A DIRECTION PARALLEL TO THE CORRUGATIONS IN A RATIO OF ABOUT 1:1 AND THE SHEET PORTIONS HAVING A SMOOTH CURVED TRANSITION HAS A CROSS-SECTIONAL TWEEN, THE TRANSITION SECTION HAS A CROSS-SECTIONAL CONFIGURAIT OF THE CORRUGATIONS WHICH IS NON-LINEAR, THE SHEET BEING SO CONSTRUCTED AND ARRANGED THAT A LIKE SHEET PLACED IN FACE TO FACE ENGAGEMENT THEREWITH WILL NEST AND NO ROTATION OF ONE SHEET ABOUT 180* IN A PLANE CONTAINING THE CORRUGATIONS THAT ADJACENT SHEETS WILL DEFINE A PLURALITY OF PASSAGEWAYS THEREBETWEEN GENERALLY PARALLEL TO THE CORRUGATIONS, THE SHEETS BEING POSITIONED WITH ADJACENT PEAKS AND TROUGHS OF THE CORRUGATIONS OF ADJACENT SHEETS IN GENERALLY CONTIGUOUS RELATIONSHIP, ADJACENT SHEETS BEING AFFIXED TO EACH OTHER. 